docs: def _embed(x, order=3, delay=1):
      """Time-delay embedding.
  
      Parameters
      ----------
      x : 1d-array, shape (n_times)
          Time series
      order : int
          Embedding dimension (order)
      delay : int
          Delay.
  
      Returns
      -------
      embedded : ndarray, shape (n_times - (order - 1) * delay, order)
          Embedded time-series.
      """
      N = len(x)
      Y = np.empty((order, N - (order - 1) * delay))
      for i in range(order):
          Y[i] = x[i * delay:i * delay + Y.shape[1]]
      return Y.T